In the prior art, a technique has been per se known for transmitting information that is displayed on the screen of an information terminal such as a portable telephone to an in-car device, and for this information to be displayed upon a display of the in-car device (refer to Patent Document #1). Furthermore, in order to make it possible to actuate the information terminal from the in-car device, it is described in Patent Document #1 to display touch switches corresponding to operating buttons and operating details of the information terminal upon a touch panel of the in-car device, and, when any one of these switches is actuated by being touched, to convert the operating command corresponding to which switch into an operating command for the information terminal, and to transmit that operating command to the information terminal. Moreover, it is also described not to display any such touch switches, but instead to employ one or more operating buttons provided to the in-car device.